This invention relates to a tool for setting threaded bushes and to a method of setting threaded bushes.
Threaded bushes are used in many ways in all sorts of applications both in industry and in the "Do-it-Yourself" field. There are three basic types of threaded bush, each of which is of a generally cylindrical hollow configuration whose cylindrical internal surface is partially threaded, the non-threaded portion being expansible to anchor the bush in an aperture. This expansion is caused by screwing the bush onto a threaded mandrel and then pulling the mandrel whilst simultaneously preventing the bush from moving with the mandrel. The first type of threaded bush is intended for use with thin sheets of material such as metallic plates. Here, the unthreaded portion is designed to collapse radially outwardly so as to clench the bush tightly against the sheet. The second type is designed for apertures in thicker sheets and has a weakened portion intermediate its threaded and unthreaded portions. The end of the threaded portion is frustoconical so that it can be pulled into the unthreaded portion to expand the latter when the bush is fractured at its weakened portion. The third type of bush is intended for use in blind bores in even thicker materials, typically in such material as chip board. Here, the unthreaded portion is provided with axial slots so that this portion can expand radially outwardly in response to axial pressure.
Most tools for setting such threaded bores are expensive power tools and so not suitable for the "do-it-yourself" enthusiast. What hand tools are available suffer from the disadvantage that it is difficult to remove the mandrel from the set bush without dismantling the setting tool.